Rotary fluid pump or motor



Oct. 7, 1941.

M. E. ESTEY ROTARY FLUID PUMP OR MOTOR Filed April 5, 1939 3 Sheets-Sheet l Invam m2 MAYNARD E, Esrsr lATT URN E'Y Oct, 7, 1941. M. E. ESTEY ROTARY FLUID PUMP OR MOTOR s Sheets-Sheet 2 Filed April 3, 1939 wn? E A. c W,

INVENT n12. MAYNARD 53 E STE?! ATT DR NET Oct. 7, 1941.

M. E. ESTEY ROTARY FLUID PUMI 0R MOTOR 3 Sheets-Sheet 3 Filed April 5, 1939 11w EDITOR MAYNARD E, E5 ET r of the rotary type.

Patented Dot. 7, 1941 UNITED STATES PATEN T OFFICE The main object of the invention is to produce a rotary pump or motor which is simple, durable and economical in construction and which is positive, accurate and dependable in operation at high speed and/or at high pressure.

Another object of the invention is to provide .a pump or motor of the above mentioned char-.

acter with control means whichmayl be readily actuated at any time during the operation of the pump or motor for varying the. capacity thereof.

Still another object of the invention resides in i the provision of a rotary fluid pump or motor in which a reversal in the direction of operation of the same may be produced. i

More specifically, my invention contemplates th provision of a pump casing having a rotor chamber therein and intake and discharge fluid passages communicating'with the rotor chamber,

the provision of a rotor having a compression or piston chamber and rotatably mounting the rotor i I attain these objects by mechanism illustrated in the accompanying drawings, in which:

Figure 1 is a plan view of a pump or motorembodying the various features of this invention. Figure 2 is a vertical longitudinal sectional view taken substantially online 2-2, Figure 1,

the lower portion of the case being broken away.

Figure 3 is. a transverse vertical sectional view taken substantially on line 3-3, Figure 2.

Figure 4 is a perspective view, partly in section, illustrating adjacent portions .of a control shaft and a supporting or guide block associated therewith. Figure 5 is a perspective view, partly insection, illustrating a bearing sleeve adapted to be associatedwith the guide block shown in Figure 4 for rotatably supporting a piston.

Figure 6 is a horizontal sectionalview through one end portion of the pump case taken substantially on line 6-6, Figure 3, illustrating my novel constructionfor providing the inlet and disin the rotor chamber so as to bring the compresnication with the fluid passages;

A further object'of the invention is to provide adjustable means associated with the pump casing for maintaining the inlet and exhaust passagesiri substantially fluid-tight connection with th piston chamber of the rotor andto compension or piston chamber: into successivecommusate for wear. i In carrying out. the above objects, I have provided two pistons, o ne of which is reciprocatively mountedin the compressionor piston chamber of the rotor. This piston in turn is provided with charg passages ofthe pump.

Figure 7 is a transverse sectional view taken substantially on line 1-1, Figure 6, illustrating a compression or pistonchamberwhich reciprocatively receives the secondjpistontherein, said second piston being rotatably supported in eccen' tric relation with the axis of rotation of the rotor so that uponrotation of the rotor a relative reciprocative movement ofthe compression or pisone of the end plates ofthe pump casingin inner face view. and one. reduced scale.

Figures 8, 9 and 10 are more or less diagram matic inner face views of an end plate of the rotorillustrating the same in different angular positions with respect to theinlet and discharge passages of the pump casing. 1

Figure 11 is a transversesectional view through the rotor similar to Figure 3 illustrating the rotor rotated one-eighth of. a revolution from the posi tion shownlin Figure 3 with the pistons. shown in their positions with respect to each other and to i the piston chamber of the rotor.

Figure 12 is a transverse sectional view similar to Figure 11 illustrating the pistons in their respective positions when the rotor and pistons are i moved substantially one-quarter of a revolution ton chambers and the pistons mounted therein is produced. I e

Aiurther object is to provide simple and durable. controlmeans whichmay be readily operated either manually or automatically for varying the relative positions of the axes of rotation of the second piston and the rotor to control the capacity of themotor or pump and/or the direction of operation thereof.

A still further object of the invention is to providethe. pistons with pressure plates or shoes for maintaining a fluid-tight connection between relatively movable surfaces of the pistons and the piston chambers.

from the position illustrated in Figure 3. e

Figure 13 is a detail sectional view taken on line l3-l3, Figure 7, illustrating an adjustable takeup for maintaining a fluid-tight connection between the inlet and discharge passages and the rotor during the rotation of the rotor.

Figure 14 is a perspective view of a piston pressur plateor shoe.

Figure 15 is a longitudinal vertical sectional view similar to Figure 2, illustrating a modified form of my novel pump structure.

Figure 16 is a transverse sectional view taken substantially on line l6-l6, Figure 1d.

Figures 17 and 18 are transverse sectional views pistons moved substantially one-eighth and onequarter of a revolution, respectively, from the positions thereof shown in Figure 16.

Figure 19 is a longitudinal sectional view taken on line |9-|9, Figure 16.

The pump or motor, illustrated in Figures 1 to 13 inclusive of the drawings, comprises a sectional case having a cylindrical central body portion 2| and two end plates 22 and 23 secured to opposite sides of the body portion as by bolts 24, the plates 22 and 23 being provided with central bearing members 25 and 26, respectively. A drive shaft 21 is rotatably mounted in the bearing member 26. The outer end of the bearing 26 may, as shown in Figure 2, be provided with a stufling box 28 for preventing leakage of fluid around the shaft 21.

The chamber 30 of the pump casing 20 is circular in cross section and has mounted thereon a rotor 3|. This rotor, as shown, is composed of a central cylindrical body portion 32 and end plates 33 and 34'connectedto the body at opposite sides thereof by a plurality of transversely extending pins or rods 35. The end plates 33 and 3 4 are provided with outwardly extending centrally disposed bosses 33' and 34, respectively, which are journaled in. suitable ball bearing members 31 mounted in recesses provided in the inner faces of the case end'plates 22 and 23. The width of the rotor 3| is such that it has a close r'unning fitjin the case chamber 36, the rods 35 being removably received in suitable aligned openings provided in the body portion 32 and side plates 33 and 34 for maintaining the body portion and side plates against relative rotary movement.

Inorder that motion may be transmitted to the rotor, the shaft 21 has the inner end thereof secured to the adjacent rotor plate 34 as by a key 39, Figure 2. The rotor body 32 is provided with a substantially rectangular opening 46 extending longitudinally ,therethrough in symmetrical relation therewith. This opening forms a piston chamber between the rotor end plates 33 and 34 for receiving a pair of pistons 4| and 42 therein. These pistons are substantially rectangular members each having an axial length substantially equal to the axial length of the piston chamber 40- to reciprocate in said chamber with a close sliding fit between the'endplates 33 and 34 of the rdtor. The width of the piston 4| is substantially equal to thethickness of the piston chamber 40 and the thickness of thepiston 4| is appreciably lessthan that of the corresponding width of the piston chamber 40 so that the piston may have a predetermined reciprocative movement through the piston chamber in one direction while being maintained against reciprocative movement in saidchamber in a direction normal to the first mentioned direction.

The piston 4| is provided with a rectangular opening 44 extending axially therethrough in symmetrical relation therewith which forms a piston chamber for receiving the piston 42 therein. The width of the piston 42 and chamber 44 in one direction normal to the length thereof is substantially equal. The width of the piston 42 is substantially equal to the thickness of the piston chamber 44, while the thickness of said piston is considerably less than the breadth of chamber 44 so that the piston may have a predetermined reciprocative movement in the chamber in the direction of the major transverse axis of the chamber.

The width or major transverse axis of the pissimilar to 16 illustrating the rotor and ton chamber 44 is arranged in right angular relation to the direction of reciprocative movement of piston 4| in chamber 40 so that'the reciprocative movements of the pistons 4| and 42 are substantially normal to each other. The inner piston 42 is rotatably mounted upon a bearing sleeve 46 which extends centrally through the piston from one end thereof to the other between the end plates 33 and 34 of the rotor 3|.

The bearing sleeve 46 is provided with a longitudinally extending opening 41 arranged in eccentric relation-to the sleeve. The opening 41 is rectangular in cross section and slidably receives therein a guide or supporting block 48 which in turn receives one end 43 of a control shaft 50 journaled in the bearing member 25 in substantially coaxial relation with the shaft 21. The block 48 has a cylindrical bearing portion 5| at one end which is rotatably received in the hub portion 33'. of the rotor end plate 33, a central portion 52 extending through thepiston'chamber 40 of the rotor 32 between the end plates 33 and 34 and a cylindrical reduced end portion 53 which is journaled in the end plate 34 adjacent the inner end of the shaft 21, as shown in Figure 2.

The width of the central portion 52 of the guide block is substantially equal to the width of the opening 41 provided in the bearing sleeve 46 so that the guide block may have free movement through the opening 41 upon relative lateral movement of the guide block and bearing sleeve. The guide block 48 is preferably ,provided, as shown in Figure 2, with an annular outwardly disposed flange 54 arranged in a suitable recess provided at the inner end of the bearing member 25 adjacent the hub 33 of the end plate 33 for maintaining the guide block against axial movement with respect to the casing 2|] and rotor 3|.

The outer'end portion 56 of the control shaft '50 is preferably of greater diameter than the inner intermediate the ends thereof to a bracket 65 carried by the bearing 25, as shown in Figure 1.

The inner end portion 49 of the control shaft is provided with a pair of pins 61 arranged in spaced relation to each other longitudinally of the shaft and which extend diametrically therethrough. The pins 61 extend outwardly beyond the shaft portion 43 through elongated guide slots 68 provided in opposite sides of the guide block portion 52 and into elongated cam slots 69 provided in the bearing sleeve 46. There are two pairs of guide slots 68, one pair for each pin 61. The guide slots of each pair extend longitudinally of the block portion 52 substantially parallel with the axis thereof so that the pins 61 may readily move through said slots during the axial movement of the shaft 50. Likewise, there are two pairs of cam slots 69 providedfin the bearing sleeve 46 one pair for each pin61. These cam slots 69 extend in angular relation to the axis of thebearing sleeve and, therefore, to the guide slots 68 provided inthe block 48.

It will be understood that during the movement of the pins 6? longitudinally through the r 2,258,379 slots 88 and 68, the bearing sleeve 46 will be caused to move laterally with respect to the guide block and control shaft 50 in one direction or the otherby the camming action of the pins 61 and slots 69 upon said sleeve, depending upon the direction of axial movement of the control shaft.

It will also be understood that during the rotation of the control shaft 50 a corresponding rotary movement of the guide block 48 and bearing sleeve 48wil1'be produced thereby due to. the engagement of the pins; 81 in the slots 88 and 88. This rotary movement of-the bearing sleeve 48, guide block 48 and control shaft 50 produces a corresponding lateral movement of the pistons 4| and 42 through the piston chamber 40 from aposition at one side .of the axis of rotation of the rotor 8| to a corresponding position at the diametrically opposite side of said axisof the rotor. This change in the poe sition of the pistons with respect to the piston chamber 40 alters the actionof the pistons so that the direction of flow of the fluid through the pump is reversed due to the coactionofsaid pistons with the fluid passages associated with thepiston chamber 40 in a manner which will hereinafter more clearly appear.

3| is provided with two pairs offiuid ports H and 12 extendingtransversely therethrough for alternately connecting the piston chambers. 48

and 44 with a pair of fluid passages "and 14 provided in the case 20. The ports H are elon gated substantially rectangular openings arranged at diametrically opposite sides of the center of the rotor plate 84 in substantially parallel relation to each other, as shown. in Figure 8. These ports are arranged substantially equal distances from the center of the plate 84 and extend through said plate substantially normal to the inner and outer side surfaces thereof as shown in Figure 2'.

The ports 12 are also elongated substantially rectangular shaped openings which are arranged at diametrically opposite sides of the center of i the plate 84 in right angular ;relation to the ports 'II. Theports I2 are arranged atopposite sides ofthe centerof the plate84 substantially equal distances from said center and intermediate the ports II, as illustrated in Figure 8. The ports 12 extend through the plate; 84 in angular relation to the inner andouter side surfaces thereof, asshown in Figure 6, the inner ends of the ports" being spaced a less distance from the center of the: plate 84 than the port while the outer ends of the ports 12 and the ports H are spaced substantially equal distances from the center of the plate. In other words, the outer end portions of the ports II and 12 are arranged to alternately communicate with the fluid passages 18 and 14,while the inner ends of the ports II and 12 are arrangedlin permanent. communication with the piston chambers 40 and 44, respectively, as indicated morelparticularly in Figure 3. i

The fluid passages 18 and 14 are each adapted to function as an inlet or discharge passage and are formed in the following novel manner:

An annular plate or ring "I8 is positioned in a corresponding annular recess '11 provided in the Oneof the end plates, as 84, of the rotor 12. The plate 18 is provided with a pair of sleeves 18, one for each opening 'I8'and'14.

The sleeves 18 may be secured in any suitable manner, as by welding, to the outer face of the plate 18 with the interior thereof inregistraare connected for conveying fluid to and from.

the passages 18 and 14. The sleeves 18 are slidably mounted in the opening 18' so that the ring 18 may be moved inwardly into close sliding fit with the adjacent outer surfaces of the rotor end plate 84.

In order that the plate 18 may be adjusted toward the rotor plate 84 to compensate for wear, a plurality of, in this instance four, screws 84 are screw-threaded in thecase end plate for contacting the outer surface of theflplatefli, as illustrated more particularly in Figures '7;and113. A lock nut 85 may be mountedon each screw 84 for securing .thescrew in the adjusted posi tion. The openings .18' and '|4'.-in the plate 116,

as illustrated in the drawings, are substantiallycircularin cross section and the plate 181s pro-' vided with a pair of channels and '81infthe' inner face thereof which extendioutwardlyfrom, the inner adjacent sides ofthe openings 18' and u 14' in substantially parallel relation with each other.

The channels 86 and 8'! are :spaced from theaxis of the plate 16 a distance substantially equal to thespacing of the ports H and outer ends of the ports 12 from the axis of rotation of the rotor8| so as to lie in the plane of said ports and alternately register therewith during the r0- tation of the rotor 8l,.as indicated diagrammatically in Figures 8, 9 and 10. i

The pistons 4| and" may be of such width that they wii have a close sliding fit inthe piston chambers 40: and 44, respectively. However,

it is preferable that the pistonsbe so constructed that the width thereof is less than the corresponding dimension or thickness of the piston chamber in which they are mounted, as indicated in Figure 3, and that the pistons be provided with pressure plates or shoes. 89 and 80 for maintaining. the pistons in fluid-tight connection with the walls of thepiston chambers extending parallel with the direction of reclproca tive movement of the pistons. These pressure plates or shoes, as shown more particularly in Figures 3 and 14, are substantially rectangular flat members of less width than one half the width of the side of the piston to which they are connected and are of substantially the same inner face of the casing end plate .23. The ring.

or plate 16 isprovided witha pair of openings 13 and 14' arranged at diametrically opposite sides thereof so as'to alternately communicate with the outer end portions of the ports 1| and length as the piston,

Each plate or shoe is provided with a laterally extending rib 9| at one side thereof which extends longitudinally of the shoe or platesubstantially midway between the longitudinal edges] thereof. The rib 8| is substantiallyseml-circular in cross section and is received in a semicircular socket82 provided in the wall of the piston, as shown in Figure 3. 1

The outersurfaces of the plates or shoes 88 and 90 are adapted to slidably contact with the adjacent wall of the respective piston chamber 48 or 44, while the ribs 9| arerotatably received in the respective sockets 92 and maintain the plates or shoes slightlyspacedgfr surface of the corresponding pis bn" to permit limited rocking movement of the shoe with respect to the piston as torque is applied to the pistons and at, the same tim maintain a substantially fluid-tight connection between the piston and the wall of the piston chamber.

The operation of the pump shown in Figures 1 to 12, inclusive, will now be understood to be substantially as follows:

Assuming that the control shaft is at its innermost position with the guide block registering in the upper portion of the opening 41, as indicated in Figures 2, 3, 6, 11 and 112, and

that the shaft 21 is rotated in a clockwise direc-.

tion, as viewed in Figures 3, Hand 12. It willnow be observed that the inner piston 42 which -is mountedupon the bearing sleeve 45 symmetrically therewith will rotate about said sleeve and, inasmuch as the piston chamber 40 revolves about the bearing sleeve-*iiF'bccentric relation thereto, the piston -42 will have a reciprocative movement with respect to the piston chamber 4| in a direction at rightangles to the plane passing through the axes of the rotor 3| and bearing sleeve 46 when the pistons and piston chambers are in the positions illustrated in Figure 3 v In a similar manner, the outer piston 4| which is mounted on the inner piston 42 in su'bstan tially symmetrical relation with the bearing sleeve 46 and, therefore, in eccentric relation with the piston chamber 40, will rotate about the axis of the bearing sleeve 46 and, therefore, in eccentric relation with the axes of rotation of piston chamber 40, rotor 3|, control shaft 50 and drive shaft 21. of piston 4| and chamber 40 in a direction substantially normal to the direction of relative reciprocative movement of piston 42 and chamber 44. When piston 4| is positioned'adjacent one end of the piston chamber 40, as illustrated in Figure 3, rotation of the rotor in a clockwise direction one-quarter of a revolution will cause the piston 4| to move to a position substantially midway between the ends of the chamber 40, as illustrated inFigure 12. As the rotor 3| continues in a clockwise direction through the second quarter of a revolution, the end of the chamber 40 which was previously spaced upwardly from the piston will 'besubstantially in h assent L This causes relative reciprocative movementcontact with the piston at the lower side there- 01, thereby producing a discharge stroke at the endof the piston chamber 40 which is uppermost in Figure 3, and a suction stroke at the end of the piston chamber which is lowermost in Figure}.

During therotation of the rotor 3| and the pistons mounted therein, the fluid passagesvl3 and 14 will be alternately brought into communication with the piston chambers 40 and 44 by the registration ofthe ports II and 12 with the passages and with the channels 86 and 31 associated -with said passages. To explain more explicitly, it will b observed that when the pistons 4| and 42 ar in the positions illustrated in Figure3, the ports H and 12 will be in the positions illustrated in Figure 8, that is, the ports II which are in registration with the ends of the piston chamber 4|! at opposlte sides of the piston 4| are positioned at oppositeends of the channels 86 and 81 out of communicatiowwith said channels and, therefore. with the passages 13 and 74. The ports I2 which have the inner aasaare of the piston chamber 54 at opposite sides of the piston 42 have the outer ends thereofrin registration with the channels 86 and 81 and, therefore, with the passages 13 and I4. As the rotor 3| is rotated one-eighth of a revolution in a clockwise directiomthe ports H and i2 will move from the position shown inFigure 8 to that shown in Figure 9. That is, the ports II will be in registration with the passages I3 and 14, respectively, while the ports 12 continue to remain in registration with said passages or with the channels 86 and 81 associated therewith,

It will thus be seen that during the movement in Figure 11, the piston 42 which is located substantially midway between the ends of the piston chamber 44 in Figure 3 will have moved toward the end of the chamber 44 adjacent the fluid passage I4, thereby increasing the area of the space between the piston and the end of the piston chamber in communication with the passage 13 and thereby producing a suction at said end of the piston chamber for drawing fluid through the inlet passage 13 and port 12 into said piston chamber.

Similarly; the opposite end of the piston chamber 44 which is in communication with the passage 14 will have decreased in area so that fluid contained in said end of the piston chamber will be forced outwardly through the port 12 registering with the passage 14 into said-passage. Slmultaneously with this action'of the piston 42, the outer piston 4| will move from the position shown in Figure 3 adjacent the lower end of the piston chamber 40 toward the opposite end thereof, therebyproducing a suction'in the end of the piston chamber 40 which is in registration with the inlet passage 13 'for drawing fluid through said passage and the port registeringtherewith into said end of the piston chamber 42; At

the same time, fluid contained in the opposite or upper end of the piston chamber 40 will be forced outwardly through the port registering with t cause piston 4| to move to a position substantially midway between the ends of the chamber 40. At the same time, relative movement of the piston 42 and piston chamber 44 will have been effected so that the piston 42 will be positioned at one end of the chamber 44. At the same time, the ports II and 12 will move from the position shown in Figure 9 to that shown in Figure 10. In other words, the ports 1| will remain in registration with the fluid passages I3 and 14, re-

spectively, for maintaining the ends of the piston chamber 40 in communication with said passages, respectively, while the ports 12 will have moved out of registration with said passages with the result the ends of the piston chamber 44 will be cut off from communication with the passages 13 and 14.

At the beginning of the next half revolution of the rotor 3|, ports 12 will move into registration with the channels 86 and thereby bring the ends of the piston chamber 44 into communication with the passages .13 and 74, respectively. As piston 42 and the piston chamber 44 are moved tor whensaid withthe ports 1 and cut oil communication of the piston chamber 13 and 14. These cycles of l operation of the piston chambers and ports may position, as illustrated in yand 42 and piston chambers 40 and 44 will, func-l j medium pacity of the p mp.

4 tion of the rotor 3 I.

mentof the control axis of thebearing sleeve 46 a and rotor It determine the capacity of the pump or the volume of a chamber while the ,tionedsubstantially midway between the ends of with respect to eachother, fluidfrom the, inlet through the dischargepassage 74.

During the second half revolution of the rotor 3| the ports II will remainin communication with the corresponding passages 13 and 14 until near the end of the complete revolution of the roports willmove out of registration and channels 1 associated therewith III with the passages continue as long drawing fluid into as the rotor is operated for the piston chambers from the 1 i inlet passage 13 and discharging the same from the piston chambers charge passage 14; 1

outwardly through the dis- When the controlshaft so is in its innermost Figure 2, the pistons 4| tion at maximum capacity. If, for any reason, it

outward axialmovement of with a cam action for producing lateral movement ofithe bearingsleevc 1", with respect to the supporting block 48 and,

thereby graduallymove the axis of the bearing willbe ,at the endof its extreme outward movement. As the axis of the bearing sleeve thus approaches theaxis of rota-, tion of the rotor, the degree of'relative movements of thepistons 4i and." and the cylinders axis of thebearing sleeve coincides with theaxislof rotation of the rotor I when the degree of relative reciprocative movements of the pistons and piston chambers capacityof the p mp,

Ill and 44 will gradually decrease and thereby, decrease the volume of fluid, caused to pass through the pump until the are wardly through the passage 74 and discharged outwardly through the passage13.

It will be understood that: the capacity of the pump may be varied after the control shaft 50 has been rotated to bring the axis of the bearing sleeve 46 above or at the opposite side of the axis of rotationof the rotor 3| from that shown h in Figure 3 byproducing longitudinal movement =of eccentricity of the of the control shait bearing sleeve with respect to the axis of therotor as explained above.

In Figures 15, l6, l7 and 18, I have illustrated a pump which functions in substantially the same manner as that shown in Figureslto 12, inclusive, with the exception that the capacity of the, pump cannot bevaried and the direction of operation cannot be changed without changing the direction of rotation of the drive shaft or the rotor.

In; the construction shown in these figures, the drive shaft, as 21 extengs through-theinterior of the pump in eccentric relation to the case chamber "and has he inner end thereof journaled in a suitable bearing member 25', provided sleeve toward the axis oLrotation of;the rotor 3| until said axes coincide, at which time the, control shaft willcease altogether and the pumping action thereof is discontinued. h l 1 When it is desiredto again increase the cathis may be readily accomplished; by moving the control shaft 50 inwardly so as to again move the axis of ,thebearing sleeve,

, intoeccntric relation with the axis of rota- Thedegree of inward moveshaft 50 and the amount of eccentricity of the fluid forced therethrough. 1 ,When iit is desired to reverse the directiongof flow of fluid through the pump without reversing bereadily'accom'plished by rotating the control 90 I the direction of rotation of the rotor'3i, this may shaft v the bearing sleeve 46 with respect to the piston 42 Journaled thereon will .reverse the posipiston 42 will remain posi-.

the chamber 44. As the rotor 3| is now rotated in a clockwise direction; the pistons and'piston chambers will function in reverse order to that, above described so that fluid will be drawn in- Ilene-half revolution. This rotation of upon pins 91, rollers 98 or compression chamber 40,

sion chamber'M mitsrotary motion through piston ll' unitary member having four laterally disposed the rotor chamber on the case and plate 22. 3 l Furthermore, the inner the drive shaft 21 the piston 42".

Inthe recesses96 are rotatably mounted, as h which project slightly beyondthe peripheral surface of the side flanges is transmitted directly to 99 defining the recess 96 into rolling contact with the peripheral surface of the case chamber 30 for rotatably supporting the rotor 3| in said "chamber. The rotor 31 is provided with a piston inwhich is mounted a piston Al; The with a piston or compreswhich receives the piston 42' for reciprocative movement piston 4| is provided therein. h

Rotation of the shaft 2'! and piston 42' transto the the rotor chamber 30 of The rotor 3|, in this instance, is a rotor 3 l mounted in the. case 20.

in the periphery thereof arranged in substantially uniform circumferential spaced relation to each other. i I i The case 20' .is provided withan inlet passage IM! and an with the side plate 23' on thecase 20 x The passages I00 and ,IOLare in';communicationwith which, .in this instance,

side plates 22' and23 of the caselfl'. h The inlet and exhaust passages are each provided with laterally disposed channels 1| Ill formed in theside plate 23-at the inner end-of, the passages. These channels I M opposite directions fromthe correspondingtpassage so as to be in 7 communication with the piston chamber 40 andu' during all but a relatively small portion of the rotary movement of the piston chambers and rotor 3|, as indicated in Figures16,17 and 18. In otherwords, the length of each channel fluid passages 10!) and II into communication witheach other byeither of the piston chambers 40" and 44 during the rotation of these chambers.

piston, as 42; is gg giroctly on the-shaft fif ahd"secured*' 'thereto as by a key so that rotary motion of recesses 96 provided exhau st passage fijll formed int, bosses Inland |ll3 connected 30' and, therefore, in direct communication with the piston ortcompression ohambersfifl' t and 44' are always in direct communication with the extend outwardly in I04 is such that the two will not be brought W respect to .ieagh other. These relative ciprocative movememmistons However, thechannels I04, like channels 86,

are of such a length that when the piston cham- 7 of the channels for connecting'said chambers with the inletvand exhaust passages and thereby eliminate back pressure in the chambers and contribute to the smooth, noiseless operation of the pump.

In operation, instead of the rotor 31' being driven directly from the source of power as in the case of the structure shown in Figures 1 to 3,

inclusive, the power is applied directly to the inner'p'iston 42 from the shaft 21'. It is thus 3 'seen that the piston 42'- transmits rotary motion to the piston 4| which in turn produces rotary motion of the rotor 3|. Rotation of the pistons W landpistonchambers'produced by the shaft 21' causes relative reciprocative motions ofthe-pis 1 justable relation with respect to said axis otrotons andtheirrespective chambersdue to the circular motions of the piston 42 and the rotor 3 about axes arranged in eccentric relation chambers causes them to, function with tive action ,for drawing fluid, such as water or .air', through the irilet passage I00 andforcing "the sameoutwardly' through the discharge passage "I;

t e 9 While I have illustrated the pistons 4! and 42 V as having direct sliding contact with adjacent s'ide walls ofthecorresp'onding chambers M1" and 44', it will be obvious that these'pistons may be provided with the'compression plates or'shoes 89,

as shown and described for the structure illus- 'trated'in Figure 3 of the drawings.

'Although I have shown and particularly described the preferred embodiments of my, invention, I do not wish to be limited to the exact construction shown as various vchanges both in the form and relation of the parts thereof may readily be made without departing from thespirit of the invention as set forth in the appended claims.

I claim:

mounted'in said' chamber having a fluid compressionchamber, fluid conveying means con- ..riecting said latter chamber withthe exterior of the case comprising a contact member mounted in. the case adjacent the rotor, fluid conduit with the case and with s'aid fluid conveying posi-' '1. In a; device of the character described, a I

having a rotor chamber' therein, a rotor of said pistons, a supporting member rotatably mounted in the rotor coaxially therewith, means operatively connecting the control member to the supporting and bearing members to rotate said latter members in unison upon rotation of the control member to bring the axis of rotation of said innermost piston from a position at one side of the'axis of rotation of the rotor to a position at the opposite side of said axis, said connecting means including drive and driven elements connected with the control and bearing members respectively coacting upon reciprocative movement of the control member to produce lateral movement of the bearing member toward and 7 tation of the rotor comprising a supporting member journaledin the rotor substantially coaxial l movement of said rotor, said pin and slot con nections between the control member and the bearing element being so constructed and arranged that said bearing element is moved with respect to the supporting member toward and from the axis of rotation of the rotor upon reciprocative movement of said control member.

4. In a fluid pump or motor, a case having inlet and discharge passages, a rotor journaled in the case, saidvrotor having endgwallsand a cylindrical body portion interposed between said end walls defining a substantiallylfiuidtight piston means for urging saidcontact member into contact with :the adiacentsurtace of the rotor,

' 2; In a'fluid pump or motor of the class wherein a'roto'r is mounted in a case to have an axis one within the otherin a piston' chamber promovements with respect to said case, a bearing member mounted in the rotor independently of the case rotatably supporting the innermost one chamber, a pair of pistons mounted in said piston chamber one within the other to reciprocate in directions normal to each other, bearing means carried by said ,rotor adapted to support the innermostone of said pistons in eccentric relation with respect to the axis' of rotationoi the rotor, said rotor having two pairs of inlet and outlet ports, onejpair for each piston," the ports of; each pair being arranged in one or' both of saidend walls adapted tosuccessively register with theinletand discharge passages respectively upon rotation of the rotorjandmeans ior cfiect= ing rotation of said-rotor. "1.1.1.

5. In a fluid pump or motor, a case having inlet and discharge fluid conveying means,"a' rotor journaled in the case, said rotor' having a substantially fluid-tight piston chamber therein, a pair of pistons mounted in said piston chamber one within the other to reciprocate in directions normal to each other, bearing means carried by said rotor adapted to rotatably support the innermost one of said pistons in eccentric relation with respect to the axis of rotation of the rotor, said rotor having two pairs of inlet and esteem y wall of the rotor, fluid conduit means operatively connected to the contact member and extending outwardly through the case, and rneans for urging said contact member into frictional engage- 5 ment with said end wall of the rotor.

MAYNARD E. ESTEY. 

